Blue-green algae identified in Halifax-area lake

Blue-green algae is popping up across Nova Scotia, but it doesn’t seem to be as bad as last year.

Elbow Lake has been added to the province’s list of sites where blue-green algae has been identified.

“As a department we have received about 30 reports of suspected blue-green algae blooms,” says Cameron Decoff, a surface water specialist with the Department of Environment and Climate Change.

Nineteen of those reports have been confirmed across the province. A number that is down from this time last year.

“We had a very early hot spell in Nova Scotia in 2024 and that translated to an early bump in the rise of actual and reported blooms. So, we did not have a hot early start to 2025,” Decoff says.

Officials with the city of Halifax are also seeing a decrease in reported cases.

“We’ve had some beaches that were closed almost for the entire summer last year and so this year we’ve actually only had one incident of blue-green algae at our beaches,” says Aquatic Services manager, Pat McGrath.

The incident McGrath was referencing was at Oakfield Park Beach, one of the city’s beaches that is monitored by lifeguards who play a role in advising people of the potential hazards of entering the water.

“With the blue-green algae, we do suggest that people don’t go swimming at all when we have blue-green algae closures at beach, lifeguards will stay on the scene to suggest people that they stay out of the water,” McGrath says.

Blue-green algae, also known as Cyanobacteria are naturally occurring microscopic bacteria that are common to freshwater lakes, rivers and streams.

Coming into contact with it can cause some minor health problems in adults.

“There will typically be limits to things like irritation of your skin nose and throat, and they can cause diarrhoea or rashes in more severe cases,” says Decoff.

He recommends checking province’s website for locations where the bacteria have been identified before heading out for a swim.

Blue-green algae tends to be present from May to October.

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